Working process of injection molding machine

Working process of injection molding machine

①Heating and plasticizing the raw material The screw is driven by the transmission system, and the plastic from the hopper is conveyed forward and compacted, and the material is gradually melted under the mixing action of the external heater of the barrel, the shearing and friction of the screw and the barrel , A certain amount of molten plastic has accumulated at the head of the barrel, and the screw retreats slowly under the pressure of the melt. The distance of retreat depends on the amount required by the metering device for one injection. When the predetermined injection amount is reached, the screw stops rotating and retreats.

② Clamp and lock the mold The mold clamping mechanism pushes the movable platen and the movable mold part of the mold installed on the movable The mold is locked.

③ The injection device moves forward. After the mold clamping is completed, the entire injection seat is pushed and moved forward so that the nozzle of the injection molding machine can fully fit the main sprue of the mold.

④ Injection and pressure keeping After the nozzle of the injection molding machine fits the gate of the mold completely, the injection hydraulic cylinder enters the high-pressure oil, pushes the screw to move forward relative to the barrel, and injects the melt accumulated at the head of the barrel into the cavity of the mold with sufficient pressure . The plastic volume shrinks due to the temperature drop. In order to ensure the compactness, dimensional accuracy and mechanical properties of the plastic parts, it is necessary to maintain a certain pressure on the melt in the mold cavity to supplement the shrinkage of the plastic parts.

⑤ Pressure relief When the melt at the gate of the mold freezes, the screw retreats, and the injection molding machine no longer exerts pressure on the melt entering the mold.

⑥ The injection device retreats. Generally speaking, after the pressure relief is completed, the screw can rotate and retreat to complete the next feeding and pre-plasticizing process. After the pre-molding is completed, the injection device withdraws from the main sprue of the mold.

⑦ Mold opening and ejection of plastic parts After the plastic parts in the mold cavity are cooled and shaped, the clamping mechanism opens the mold and pushes out the plastic parts in the mold.

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